Pressure sensing equipment is often used within the aerodynamic research field. The sensing equipment may be used in many applications such as windtunnel, flight test, and turbomachinery testing. For example, sensing equipment may be used in wind tunnel applications during the development of wing designs. Pressure sensing equipment may also be used for in-flight test applications such as monitoring the pressure conditions observed by a test missile, both around the missile and in crucial engine areas such as the inlet, combustor, and nozzle. For aerodynamic research, miniature pressure measurement instrumentation may be used that incorporates piezoresistive pressure sensor arrays of individual sensors. These miniature instruments, also called pressure scanners, may incorporate electronic multiplexers at the product's sensor substrate level for individual sensor selection to connect to an attached amplifier or other electronic circuit. Current state of the art miniature pressure scanners include the ESP line of miniature pressure scanners (e.g ESP-16HD, ESP-32HD, and ESP-64HD miniature pressure scanners) manufactured by Measurement Specialties, Inc. Pressure Systems and as described in the ESP Pressure Scanner User's Manual, dated August 2009, the subject matter thereof incorporated herein by reference in its entirety.
In a typical application, hundreds or even thousands of individual pressure sensors may be used and monitored in an aerospace application, with Bipolar and CMOS based multiplexers typically considered for such scanning needs. The need to scan across these sensors through the multiplexer at increasingly faster speeds has highlighted several problems relating to fast sensor settling times for pressure scanners. Limiting factors include a multiplexer's inherent charge injection, capacitance and resistance characteristics, and the pressure sensors' relatively high source impedance. In particular, during switching, voltage spikes are created on the multiplexed signals coming from each pressure sensor and through the multiplexer. These spikes must settle and decay in order for the signal line to return to its true value so that an accurate reading may be made. In addition, it has been observed that when pressure sensing equipment is used at higher ambient temperatures, the settling time for the voltage spikes is increased.
Alternate systems and methods for miniature electronic pressure scanning that reduce the settling time of multiplexer voltage spikes are desired.